There is a phenomena that I was previously unaware of before I began taking jobs entering data. I was blissfully unaware until one day, a colleague pointed it out to me.
There is a group of people who don't know that letters are not numbers.
Yes. It is a fact.
You see, when I enter my apartment number, I just merely state that it is APT 346. Or some people who don't have an apartment number but merely have a suite number or floor number or house number...you get the idea. Occasionally, rather than denoting what time of space it is, the person will get lazy and write "#99" or something similar.
But there is a section of housing, out there in the world, that doesn't exist with numbers. Things are lettered, instead. Like Apt B, Suite D...and so on.
Which is fine. Mostly. Except this leads people to write this as their address:
385 Made Up Street #B
Seriously. When you say it out loud, you say, "Number B" which isn't a thing. It is a letter. Big Bird will tell you that.
You shouldn't think too long on this. Because, after all, this means that the people who do this probably write that they live at #B every time they write their address out. Like they don't realize that what they are writing isn't a thing. Ever.
(NOTE: I do realize that sometimes letters are used in mathematical equations. But they are mostly just standing in for numbers. Not part of the number. And imaginary numbers never count.)